This invention relates to micropipette pullers of the type shown in my earlier U.S. Pat. No. 4,600,424 granted July 15, 1986. Micropipette pullers generally employ a filament comprising a heated metal band or wire bent into a ring to surround the glass tubing and heat it to its melting point. The shape of the micropipette is dependent largely upon the shape of the filament and various types of filaments are available for the production of different shapes and lengths of micropipettes. However, a change in the shape and type of filament often produces a significant change in the heating characteristic, and the shape of the micropipette is difficult to control and replicate.
The better micropipette pullers are now all computerized so that the variables in the pulling process, such as filament temperature, length of the pull, the strength of the pull and the rate at which the glass is cooled may be programmed into the puller. Efforts have also been made to move the filament during the pulling cycle in order to heat a greater area, but the movement of the filament was very difficult to program in a repeatable manner.